Means for holding printing plates



July 6,. 1937. H. A. w; W OO D MEANS FOR HOLDING PRINTING PLATES Original Filed Aug. 9, 1932 2 Sheets-Sheet l N. MT Aw H. A. W. WOOD MEANS FOR HOLDING PRINTING PLATES 7 July 6, 1937.

2 Sheets-sheaf 2 1 Original Filed Aug. 9, 1932 4, da -n 4 UNETED 2,086,145 MEANS FOR Hominid PitIN'riNG PLATES Henry A. Wise Wood, New York, N. lL, assignor to Wood Newspaper Machinery Corporation, New York, N. Y., a corporation of Virginia Application August 9, 1932, Serial No.-628,071 Renewed December 7, 1936 5 Claims.

This invention relates to the holding of printing plates to prevent the bowing out of the plates on the printing cylinders while the cylinders are rotating at high speed.

The principal object of the invention is to provide means for holding the plates at points other than the edges to prevent the bowing action above described, the same to be used with ordinary plate clamps and more specifically to provide means for holding the plates at points on the backs of the plates. Another object of the invention is to provide this plate holding means in such a position that when the plate is placed on the cylinder the plate holding means will enter the plate without any change in the direction of motion of the plate relative to the cylinder. vide for accomplishing these results in an extremely simple and inexpensive manner.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawings, in which Fig. l is a plan, partially in section, of a plate cylinder carrying printing plates and showing the intermediate devices for holding the plates;

Fig. 2 is a cross section of a printing cylinder showing a simple form of the plate holding means;

Fig. 3 is a similar view showing a preferred embodiment of the invention, and

Fig. 4 is a side view of the same, taken inthe direction of the arrow 38 in Fig. 3, but with the plate not shown.

By experience I have found that the customary bevel plate clamps for holding semi-cylindrical plates on printing press cylinders are insufficient to secure the plates properly to the cylinders of high speed printing presses and they allow the plates to bow out at certain places. The bowing out occurs at two points on semi-cylindrical plates, each about a quarter of a semi-circle from the edge of the plate. In addition to the plate clamps, bars are used along the straight edges parallel with the axis of the cylinder for holding the straight edges down. This considerably improves the holding of the plate but does not always entirely eliminate the bowing of the plate outwardly on the cylinder.

This invention is designed chiefly to prevent the bowing of the plate at a point substantially half way between the center and edge of the plate when held by any usual bevel clamps and longitudinal edge bars.

Referring to the drawings, the plate cylinder I carries plates 2 and 3 held in a customary manner Another object is to proby a center ring centering clips 5 and end clamps 6 and having in addition margin T-bars 1 for holding the straight edges of the plates.

According to this invention the difficulty above described is avoided by the adoption of means for holding the plates at points intermediate the edges of the plates or, in other Words, points between two T-bars l and between two of the end clamping means, such as the center ring, center clips and end clamps. i

In the form shown in Figs. land 2, the additional holding means comprises one or more longitudinal bars 3 on each half of the plate fixed in the cylinder I and projecting parallel to each other into the plate. They are located in such a manner that their long dimensions are parallel with the direction of motion by which the plate is applied to the cylinder, as indicated at the top of Fig. 2. The plate itself is cast with notches 9 in the concave back into which these bars will enter when the plate is placed in the cylinder in the customary manner, as is shown in the bottom of Fig. 2. This permits the plate to be placed in position in the customary manner.

Inasmuch as the bars 8 are shown at the points where the plate bows out in ordinary practice, the underslung edges of the recesses 9 in the plates catch beneath the straight .sides of the bars preventing the plate from bulging out at this point by the pressure of the plate clamps or when the press is brought up to speed and the highest amount of centrifugal force is applied. At the same time the plates not only can be applied in the usual way but they can be removed from the 7 cylinder without any different manipulation than has been used. They exert their force at points half way between the center and edge of the plate to prevent the area of the plate in which they lie from moving away fromthe cylinder.

In the form shown in Fig. 4' projections or bars l8 are held by pins it. The projections or bars l8 perform the same function as the bars 8, being essentially interrupted bars, the recesses for which are less likely to decrease the strength of the plate than those for continuous bars.

It will be seen that the printing plate can be cast in the usual way in a stereotype plate mold with the cavities or notches 9 cast in place for fitting the bars 8. It is obvious therefore that this is a practical and useful means for manufacturing stereotype plates so that they may be fitted on printing cylinders. inexpensive means is provided for holding them at a distance from the edge of the plate. It will be obvious also that the usual means for holding Thus simple a and the plate on the four edges enables the plate to be securely attached, while the holding bars prevent high spots on the plate due to the bulging and therefore is conducive to good printing.

Although I have illustrated and described only one form of the invention I am aware of the fact that modifications can be made therein by any person skilled in the art without departing from the scope or" the invention as expressed in the claims. Therefore, I do not wish to be limited in this respect otherwise than as set forth in the claims, but what I claim is:

1. The combination with a printing plate cylinder, a printing plate thereon and margin bars extending longitudinally of the cylinder for holding the edges of the plate, of holding bars for holding the plate against bulging at a quarter of the Way around the plate from the edges of the margin bars, said holding bars being located perpendicular to the diameter drawn through the cylinder from one margin bar to the other, whereby the plate can be applied and removed in the usual manner.

2. A printing plate cylinder having margin bars and two series of bars projecting in parallel directions therefrom at a distance from the margin bars and in the direction in which a plate is applied to the cylinder or removed therefrom and projecting beyond the surface of the cylinder, said bars having straight surfaces on their sides toward the center of the plate.

3. A printing plate cylinder having bars projecting in parallel directions therefrom and in the direction in which a plate is applied to the cylinder or removed therefrom and projecting beyond the surface of the cylinder, and a plurality of parallel pins in offset planes extending into the cylinder and through the bars for holding the bars firmly in position.

4. A printing plate cylinder having fixed nonaxial bars projecting in parallel directions therefrom and in the direction in which a plate is applied to the cylinder or removed therefrom and projecting beyond the surface of the cylinder at a plurality of points around its semi-circumference.

5. The combination with a printing plate cylinder, and a printing plate thereon, of holding bars for holding the plate against bulging at a quarter of the way around the plate from the edges of the plate, said holding bars being located perpendicular to the diameter drawn through the cylinder from one straight edge of the plate to the other, whereby the plate can be applied and removed in the usual manner.

HENRY A. WISE WOOD. 

